A recent Oakland Tribune editorial against the initiative gets key facts wrong. The editorial, which was widely published in other newspapers, claims that the proposal has a zero-tolerance for accidental GMO content in foods that aren't labeled as containing GMOs. Such a policy would force producers of essentially non-GMO products to use the label "may contain GMOs," simply out of fear of litigation. But the editorial is mistaken. The initiative rightly allows foods that do not intentionally contain GMOs to carry a "non-GMO" label.

The initiative has several moderate and reasonable features. For example, it would require genetically modified animals -- such as a fast-growing genetically modified salmon -- to contain a "GMO" label, but it would not require such a label for ordinary beef that had been fed genetically modified corn and soybeans. A farmer or food manufacturer would not have to do any fancy testing to prevent accidental contamination with GMOs (for example by drifting seeds from a neighboring field, or from GMO-containing dust left over on farm machinery). It suffices for the food producers to claim in writing that they used crop varieties and food ingredients that they reasonably believed were not genetically modified. For example, a food manufacturer purchasing non-GMO corn would have to get the supplier to sign such an affidavit, but would not have to do scientific testing. Some anti-GMO advocates might have wanted stricter rules, but there are good common-sense reasons why the initiative took these positions.

In this context, the Oakland Tribune editorial is particularly disappointing. Whether you support or oppose GMOs, it is important to explain the initiative clearly so that our democracy can function as well as possible.

The Tribune editorial echoed a point that was also made in a recent working paper by the highly esteemed agricultural economist Colin Carter and several coauthors. They wrote:

The California initiative would implement a zero-tolerance policy for accidental presence of small amounts of GM substances, even if the U.S. government has approved the GM material for human consumption.

But, after reading the text of the initiative, this seems incorrect. I wrote Professor Carter to ask about this, and his brief response by email while traveling made several good points in opposition to Prop 37, but didn't really back up this claim that the initiative takes a zero-tolerance position on accidental contamination. Essentially, opponents fear that firms will anticipate legal problems and prophylactically label their products with "may contain GMO" labels, but I cannot really find a reasonable basis for that fear in the initiative itself.

There are good reasons why some people will oppose this California Prop 37. GMO technologies may well not be dangerous to humans. Or they may have some risks and tradeoffs, just as non-GMO foods do, that are worthwhile because of the production advantages from the new technology. Or, as economists in particular are likely to point out, it may be that a well-crafted voluntary labeling regime would have functioned as well as mandatory labeling without as much burden on society. Still, opponents should make those points clearly rather than mischaracterizing Prop 37.